1. Field of the Invention
This invention relates to composition of matter useful in dental hygiene, more specifically in the prevention of caries.
2. Description of the Prior Art
One of the significant factors in the formation of caries is the conversion of soluble carbohydrates into acids. Inportant ingredients in this conversion process are the various types of lactic acid producing bacteria, including the genus Streptococcus. Accordingly, antibacterial substances have been added to toothpaste, rinses and other oral hygiene agents to control the growth and metabolism of oral bacteria and thereby eliminate or reduce the production of acids. The substances heretofore used to suppress bacterial growth have been characterized by a broad spectrum of activity which results in a marked change in the qualitative and quantitative composition of the microbial oral flora. These drastic changes are undersirable because many of the bacteria which are eliminated are beneficial for proper oral hygiene.
Recent studies (see, for instance, J. D. De Stoppelaar "Streptococcus mutans, Streptococcus sanguis and dental caries", dissertation Utrecht, 1st June 1971), have shown that although the production of acid from sugars, particularly by lactic acid bacteria, is a factor in the chain of caries formation, acid alone will not cause significant amounts of caries. These studies have established that the formation of "plaque", an insoluble, strongly adhering layer, is the primary factor in the causative chain. Acid producing bacteria and sugars which have been diffused into the plague cause local acid production on or near the tooth surface. Animal tests have shown that such local production of acid is a direct cause of caries.
Streptococcus mutans (by its action on saccharose) has been identified as the only bacteria in the oral cavity which excretes the plaque forming, insoluble, high-molecular weight carbohydrate. Therefore, the suppression of the growth of Streptococcus mutans would significantly reduce caries formation by eliminating the formation of plague.
A number of years ago a comparative study (A. Kaars Sijpesteijn et al., On the Antifugal and Antibacterial Activity of Some Trisubstituted Organogermanium, Organotin and Organolead Compounds, 28 Antonie van Leeuwenhoek 346 (1962) showed triorgano germanium compounds, unlike the corresponding triorgano tin and lead compounds, have only slight antimicrobial effect. A few years later (A. Kaars Sijpesteijn et al., Antimicrobial Activity of Trialkylgermanium Acetates and the Influence of the Medium, 30 Antonie van Leeuwenhoek 113 (1964) it was found that some types of lactic acid bacteria displayed a high sensitivity to triorgano germanium compounds, particularly tributyl germanium compounds. For instance, Streptococcus lactis and Streptococcus mitis appeared to be very sensitive. However, Streptococcus faecalis was found to be entirely insensitive to tributyl germanium acetate. It was further observed that the activity of some tributyl germanium compounds is affected by the presence of slight amounts of blood or blood constituents in the nutrient medium. Thus some Streptococcus species, such as Streptococcus lactis, are ineffective in the presence of blood or blood constituents, while others, such as Streptococcus mitis, are not affected by their presences. From these and other studies neither the sensitivity nor insensitivity of certain Streptococcus species to triorgano germanium compounds nor the effect on the sensitivity of blood or blood constituents in the nutrient medium can be predicted rationally.